Evaluation of the corrosion behavior of low-temperature nitrided AISI 316L austenitic stainless steel

Low-temperature nitriding of austenitic stainless steels allows the formation of a supersaturated solid solution of nitrogen in the austenite lattice (expanded austenite or S-phase), while inhibiting the precipitation of Cr nitrides. The corrosion behavior of the nitrided layers depends on their microstructure and phase composition, as well as on the environment characteristics. The testing conditions can also play a role, as observed when the repassivation characteristics are assessed. The aim of the present study is to evaluate the corrosion behavior of low-temperature nitrided AISI 316L austenitic stainless steel using different electrochemical techniques, and, in particular, to assess the repassivation capability in NaCl solution.